20513250 has 80 divisors (see below), whose sum is σ = 57420792. Its totient is φ = 5464800.

The previous prime is 20513231. The next prime is 20513257. The reversal of 20513250 is 5231502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 826281 + 19686969 = 909^2 + 4437^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (20513257) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 19744 + ... + 20756.

Almost surely, 2^20513250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20513250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28710396).

20513250 is an abundant number, since it is smaller than the sum of its proper divisors (36907542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20513250 is a wasteful number, since it uses less digits than its factorization.

20513250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042 (or 1023 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 20513250 is about 4529.1555504310. The cubic root of 20513250 is about 273.7441357348.

Adding to 20513250 its reverse (5231502), we get a palindrome (25744752).

The spelling of 20513250 in words is "twenty million, five hundred thirteen thousand, two hundred fifty".